Instead, why not buy a B put, and sell an A put? Then if $A < p < B$, you can't be assigned, and your B put is ITM. So you profit more!
This is going to get ugly :->)
There are 6 basic synthetic positions relating to combinations of put options, call options and their underlying stock (the Synthetic Triangle):
- Synthetic Long Stock = Long Call + Short Put
- Synthetic Short Stock = Short Call + Long Put
- Synthetic Long Call = Long Stock + Long Put
- Synthetic Short Call = Short Stock + Short Put
- Synthetic Short Put = Long Stock + Short Call
- Synthetic Long Put = Short Stock + Long Call
These are all variations of S + P - C = 0
Suppose the strike prices of your short put spread are -$50p and +45p then by using #s 5 and 6 from above:
-50p = +STK - 50c
+45p = -STK + 45c
Add the two equations together and you get:
-50p + 45p = 45c - 50c
Therefore, selling the 50/45 put spread is equivalent to buying to 45/50 call spread and NOT as you suggested, just reversing the buy and sell of the respective puts in the spread.
Instead, why not buy a B put, and sell an A put?
That is a different strategy, a bear/debit put spread, equivalent to a bear/credit call spread, which is shown in your other question. If you are comparing the value of the position for a given $p$, you must take into account that a debit spread costs cash up front, whereas a credit spread pays cash up front. The profit/loss plot includes this cash component. You cannot compare the value of the options alone.